Heritage Action, the political arm of the conservative Heritage Foundation, spent last year’s August recess banging the drum for Congress to defund the 2010 health law, barnstorming the country to fuel conservatives’ discontent with GOP leaders in Washington. The resulting standoff briefly shuttered the government.

This year, the group is issuing a broader call-to-arms, challenging conservatives to renew their commitment to an agenda that champions a more-robust foreign policy and elevates marriage and religious liberty, as well as the same free-market economic populism that characterized its earlier initiatives.

A memo to be released Thursday and distributed to members of Congress before they leave town for the five-week August recess, serves as a wake-up call to conservatives that voters still need to hear a positive governing agenda from the GOP before they will be willing to elect a new Republican majority.

“There are a lot of people sitting back right now and expecting a wave to materialize and carry them across the finish line,” said Mike Needham, chief executive of Heritage Action, referring to congressional Republicans. “That is terrifying as a conservative. We have to be the ones who still have to make that case.”

Heritage Action outlined some of its top legislative priorities in the treatise, including familiar items like the elimination of Fannie Mae and Freddie Mac and tax reform that scraps loopholes, lowers rates and taxes consumption over saving.

The group also devotes a large chunk of its messaging memo to the defense of marriage and religious freedom. The group applauds the recent Supreme Court decision allowing certain small, privately owned businesses to limit health coverage for drugs or procedures that contradict their personal religious beliefs.

It goes a step further by calling for additional protections, citing businesses that “have been hauled into court because they declined to provide their services for a same-sex ceremony in violation of their religious beliefs.”

That emphasis on the family and religion is meant as a stern rebuke to Republicans who want to focus solely on fiscal issues and the economy, Mr. Needham said. “There are some people who think the future of the Republican Party is to stop talking about the family and stop talking about civil society,” he said. “That is the wrong way to go.”

Despite polls that show a growing reluctance by Americans of every political stripe to engage in foreign conflicts, Heritage Action advocates an “unashamed projection of American strength aimed at deterring threats before they materialize.” It cites continued hostilities in the Middle East, Russia’s increasingly aggressive posture in Eastern Europe, and China’s efforts to test maritime boundaries. In the document, the group calls for increased troop levels, upgraded weapons systems and more transparency in the procurement process.

“American leadership is necessary to keep the world safe,” Mr. Needham said, arguing for a balance “between having a strong foreign policy” that “also recognizes that we can’t be the world’s policeman.” He added, “This is a country that, at its core, is not an isolationist country.”

The sharply worded document, from a group accustomed to criticizing GOP leaders, serves as much as a challenge to Republicans to define what the party is about as it as a criticism of President Barack Obama. Mr. Needham argues Republicans must do a better job connecting with Americans of all political perspectives who are frustrated with Washington and feel the political and economic system is stacked against them.

“The only way to win an argument is to have one,” the Heritage Action document reads. “And while many people think Washington, D.C., is broken, the truth is that it’s broken only for the American people. For the wealthy and the powerful, Washington is a finely tuned machine aimed at avoiding principled arguments and keeping the gravy train rolling for well-connected interests.”

Many Republicans, including House Speaker John Boehner (R., Ohio), blamed the group for leading the GOP into the government shutdown without a workable exit strategy. The strife that defined the GOP at the time has since subsided, and a string of competitive primaries in which most of the incumbents and leadership-backed candidates survived conservative challenges.

Heritage Action’s latest treatise is meant to serve as a rallying cry for conservatives to starting beating the drums again.

“Washington has retreated into its tortoise shell,” Mr. Needham said. “It’s time to get back on offense.”

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